1. Field of the Invention
The present invention relates to a method and means for fixing joint prostheses.
2. Related Art and Technology
A common method of anchoring a joint prosthesis is cementing it to bone tissue, i.e. filling a gap between the joint prosthesis and the osseous wall with bone cement. The problem of unsatisfactory long-term fixation of cemented prostheses has resulted in that use is now less frequently made of cement for fixing prostheses. In this context, it is vital that the shape of the prosthesis stem, which is inserted in the cavity reamed in the bone, conforms well with the shape of the cavity, and that the bridging distance between the osseous wall and the surface of the prosthesis stem is as short as possible to allow bone tissue to form and, within a reasonable time, grow onto the prosthesis from all sides to anchore it to the osseous wall. The minimum bridging distance is of course a true physical contact between the prosthesis surface and the osseous wall but, in a joint prosthesis in a bone, it is highly unlikely that such contact can be established other than at points, which is not sufficient. It is difficult to combine the cementless method, consisting in establishing such a physical contact and providing good long-term fixation but poor short-term fixation, with the method using bone cement which provides good short-term fixation but poor long-term fixation, since the bone cement isolates the prosthesis surface from the osseous wall.